In general, the demand for secondary batteries is rapidly increasing due to increased technical development of and demands for the mobile devices. Lithium (ion/polymer) secondary batteries having high energy density, operation voltage, and superior preservation and lifespan characteristics are widely used as energy sources for various mobile devices as well as electronic products.
A pouch type secondary battery improved in terms of safety is disclosed in Korean Patent Publication Gazette No. 2009-0065587. In the pouch type secondary battery of the related art, there is a channel formed in a cell and in a sealing part of an electrode tab. When gas is excessively generated in the pouch due to overcharging or an internal short circuit and increases the internal pressure of the pouch, the gas may be exhausted to the outside of the pouch through the channel. That is, since the gas is always exhausted through the sealing part of the electrode tab when the gas within the cell is exhausted, the direction in which the gas is exhausted may be predicted.
Of course, in the case of a specific electronic device or mechanical device, it is fine if gas is exhausted through a part adjacent to the electrode tab of the pouch type secondary battery.
Alternatively, in the case of another electronic device or mechanical device, a device sensitive to heat or gas may be disposed adjacent to the electrode tab of the pouch type secondary battery. Thus, in order to prevent the device sensitive to heat or gas from being damaged or corroded, the gas may be exhausted through another part that is not adjacent to the electrode tab of the pouch type secondary battery.
However, in order to mount the pouch type secondary battery disclosed in the above-described publication gazette into a mechanical or electronic device, the design of the mechanical or electronic device has to be changed so that the device sensitive to heat or gas is not disposed adjacent to the electrode tab. Therefore, such a pouch type secondary battery may not be mounted into a mechanical or electronic device for which a change in design is not possible.